The present invention relates in general to nail enamel compositions, and more particularly, to nail enamel compositions containing aluminum platelets for forming a film having a mirrorlike appearance over natural or synthetic human nails.
Nail enamel compositions include a class of nail care products regularly used by women as part of their beauty care routine. These nail care products are available in a multitude of product formulations, from clears to a variety of colors. Typically, clear nail enamel compositions include a film forming polymer, a film forming resin, a plasticizer and one or more solvents. In the case of a color nail enamel composition, the product may also include a thixotropic compound, a suspending agent and one or more pigments, or in the alternative, an organic coloring polymer may be used. In addition to these components, a number of optional and proprietary components are often included such as UV light absorbers, moisturizers, stabilizers, fragrances and the like.
Nail enamel compositions have heretofore been formulated in an infinite number of colors. Often, the manufacturers would produce nail enamel compositions having the same popular colors as their competitors. This provided little distinction between nail enamel products of different manufacturers to the ultimate consumer. Nail enamel compositions having a more decorative appearance were produced by including small pieces of light reflecting, decorative material known as glitters within the composition.
Other attempts to enhance the decorative appearance of nail enamel compositions has been the use of metallic pigments. By way of example, there has been known the use of metallic pigments in the nature of aluminum platelets having a controlled particle size and uniform thickness. Aluminum platelets of the foregoing characteristics which have been incorporated into nail enamel compositions are available from Avery Dennison Corporation of Pasadena, Calif. which are sold under the mark Metalure(copyright) through Obron Atlanta Corp. of Hainesville, Ohio. The aluminum platelets are supplied in a dispersion or suspension as a slurry dispersed in various solvents compatible for formulation in vehicles for rotogravure and flexographic printing inks, and in base vehicles and clear coats for spray applications.
The nail enamel composition incorporating aluminum platelets contained nitrocellulose RS xc2xd sec. (M.W. xe2x88x9256,000) as the film forming component. The films when applied over natural or synthetic human nails had a generally dull silver appearance. Although the silver appearance provided a unique and decorative look to the nail enamel composition, the dull nature detracted from its aesthetic value. The metallic appearance was further deteriorated by the inclusion of suspending agents required to support the aluminum platelets in the nail enamel composition.
Despite these known nail enamel compositions having aluminum platelets, there has heretofore been unknown nail enamel compositions which when applied to natural or synthetic human nails will produce a film having a mirrorlike appearance.
The present invention discloses a nail enamel composition having a mirrorlike appearance. The nail enamel composition includes aluminum particles in the nature of platelets which, in accordance with one example, are sold under the mark Metalure(copyright). The Metalure(copyright) dispersions or suspensions are commercially available in eight different vehicles systems as follows:
The preferred dispersion or suspension of aluminum platelets are those dispersed in ethyl acetate, Metalure(copyright) Product No. L-55350. In addition to being dispersed in a solvent compatible in nail enamel compositions, it has a relatively low viscosity compared to the other available dispersions or suspensions. The low viscosity is preferred in view of the high molecular weight film forming components incorporated into the nail enamel composition of the present invention as to be described. However, it is to be understood that the other designated dispersions or suspensions of the aluminum platelets, and mixtures thereof, can also be incorporated into the nail enamel compositions of the present invention, including those from other sources. For example, aluminum platelets are also available from Silberline Manufacturing Co., Inc. of Tamaqua, Pa. under the mark STARDRITE 1100 EAC. The aluminum platelets are provided as a 10% dispersion in ethyl acetate. Aluminum platelets are also available from MD-Both Industries of Ashland, Mass. under the marks Metasheen NC Dispersion and Metasheen N1000 Dispersion. The aluminum platelets are provided as a 5% dispersion in a mixed organic solvent/nitrocellulose base.
As previously discussed, nail enamel compositions incorporating aluminum platelets have heretofore been known. These compositions were based upon incorporation of aluminum platelets in nitrocellulose RSxc2xd sec. as the film forming component. The percent solids in the known composition was in the range of about 25-32% by weight. The known nail enamel composition although having an aluminum color appearance did not have a mirrorlike appearance, i.e., having a dull silver appearance.
In accordance with the present invention, it has been discovered that nail enamel compositions containing aluminum platelets can be formulated to have a mirrorlike appearance. To this end, it has been discovered that by incorporating one or more film forming components into the nail enamel composition having higher molecular weights, the resulting composition will produce a film having a mirrorlike appearance. The film forming component can be selected from a variety of polymers such as those well known for use in nail enamel compositions. As a result of the higher molecular weight film forming components, the solid content of the nail enamel composition is generally lower than heretofore known, for example, in the order of about 4 to about 20% by weight.
In accordance with one embodiment of the present invention there is described a nail enamel composition of non-toxic components for forming a film over natural or synthetic human nails, the composition comprising a film forming component, a solvent and aluminum platelets, the film having a haze value greater than 932 HU. Non-toxic components include those components which are suitable for use in nail enamel compositions. Toxic compounds which are not suitable for use in nail enamel compositions include those which have been banned under state or federal law, or those which are known or suspected to be toxic to humans.
In accordance with another embodiment of the present invention there is described a nail enamel composition of non-toxic components for forming a film over natural or synthetic human nails, the composition comprising nitrocellulose having a molecular weight greater than 56,000, a solvent and aluminum platelets.
In accordance with another embodiment of the present invention there is described a method of forming a film containing aluminum platelets over natural or synthetic human nails, the method comprising coating a natural or synthetic human nail with an aqueous nail enamel composition to form a first film, and applying a nail enamel composition comprising a film forming component, a solvent and aluminum platelets over the first film to form a second film thereover, wherein the second film has a haze value when applied over the first film greater than a haze value when applied directly over said natural or synthetic human nails.
In accordance with another embodiment of the present invention there is described a nail enamel composition of non-toxic components for forming a film over natural or synthetic human nails, the composition comprising a film forming component, a solvent and aluminum platelets, wherein the solid content of the composition is in the range of from about 4 to about 20% by weight.
In accordance with another embodiment of the present invention there is described a nail enamel composition of non-toxic components for forming a film over natural or synthetic human nails, the composition comprising nitrocellulose having a molecular weight greater than 56,000, a solvent, a plasticizer, a suspending agent and aluminum platelets, the aluminum platelets having an aspect ratio of between about 1.0 to about 5.2 and a length in the range of about 3.6 microns to about 45.3 microns, the film having a haze value of about 975 HU and greater.
In describing the preferred embodiments of the present invention, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and is to be understood that each specific term includes all technical equivalence which operate in a similar manner to accomplish a similar purpose.
Nail enamel compositions of the present invention for coating natural or synthetic human nails broadly include the ingredients of one or more film forming components, one or more solvents and aluminum particles in the form of platelets. The resulting composition will provide a nail enamel which forms a film upon drying having a mirrorlike appearance. In addition to the above components, the nail enamel compositions according to the present invention may further include one or more additional ingredients, for example, a thixotropic compound, a suspending agent, plasticizers, secondary pigments or colorants, one or more film forming resins, UV light absorbers, stabilizers, fragrances, moisturizers, leveling agents, drying agents and the like. In addition, if desired, the nail enamel compositions of the present invention may also include other pigments or organic coloring polymers to alter the film appearance as desired.
The nail enamel compositions of the present invention contain one or more primary film forming components such as polymers and the like. For example, suitable film forming compounds include cellulose acetate, cellulose acetate butyrate, ethyl cellulose, vinyl polymers, nitrocellulose, methacrylate and acrylate type polymers and co-polymers, and mixtures thereof. The preferred primary film forming compound for use in the present invention is nitrocellulose which provides an unusual combination of properties of toughness, durability, solubility and solvent release. Nitrocellulose is typically supplied in 70% concentrations, wet with 30% ethyl or isopropyl alcohol. As used in the present application, the percentage of nitrocellulose is given in a composition will be on a dry basis.
It has been discovered that film forming compounds having higher molecular weights will produce films having a mirrorlike appearance when incorporating aluminum platelets. In this regard, it was determined that as the molecular weight of the film forming compound increased, the mirrorlike appearance of the resulting nail enamel film improved as measured by its haze property as to be described hereinafter. By way of example, nitrocellulose as the film forming compound having an average molecular weight greater than 56,000 show improvements in mirror appearance. To this end, nitrocellulose as a film forming compound is available from a variety of sources, for example, Hercules, Inc. in various molecular weights. These grades of nitrocellulose include nitrocellulose RSxc2xd sec. having a molecular weight of 56,000, nitrocellulose RS5-6 sec. having a molecular weight of 112,000, nitrocellulose RS15 sec. having a molecular weight of 130,000, nitrocellulose RS60-80 sec. having a molecular weight of 175,000, nitrocellulose RS150 sec. having a molecular weight of 190,000, as well as other grades having both lower and higher molecular weights.
Although nitrocellulose having higher molecular weights can also be used in the compositions of the present invention, they are less desirable due to their increased viscosity. It is contemplated that various grades of nitrocellulose can be used in combination as the film forming compounds of the present invention. For example, mixtures of low and high molecular weight nitrocellulose can be incorporated into the nail enamel compositions of the present invention to produce a film having a mirrorlike appearance. In particular, to improve the wear characteristics of the resulting film, the solid content of the nail enamel composition can be increased by using a mixture of lower grade nitrocellulose, e.g., RSxc2xc sec., and higher grade nitrocellulose, e.g., RS60-80 sec.
Other film forming compounds include cellulose acetate butyrate Product No. 381-20 having a molecular weight of about 83,000 which is available from Eastman. It is contemplated that other film forming compounds can be used having molecular weights sufficiently high to provide a nail enamel composition having enhanced mirror appearance. Nail enamel compositions of the present invention may include the above film forming compounds, their equivalence and combinations thereof in an amount ranging from about 2 to about 15% by weight, and more preferably in the range of about 4 to about 8% by weight of the composition.
In addition to the aforementioned film forming compounds, the nail enamel compositions can also include one or more modifying resins. Exemplary film resins which may be used in the present invention in combination with the film forming compounds include, for example, drying and non-drying alkyd resins, polyvinyl resins for example polyvinyl acetate, polyester resins, epoxy resins, acrylic polymers and copolymers, maleic modified glycerol esters of rosin, and toluene sulfonamide/epoxy resins, e.g., tosylamide epoxy resin. It is also within the scope of the present invention to include aldehyde condensation products such as arylsulfonamide formaldehyde resins, specifically toluene sulfonamide formaldehyde resin which is a condensation product of formaldehyde and toluene sulfonamide.
In addition to the film forming compounds, the nail enamel compositions according to the present invention may include at least one plasticizer to soften and plasticize particularly the film forming compounds. The plasticizer may be in either liquid or solid form, as well as combinations thereof. The compositions may include one or more of the known plasticizers which are suitable for use in nail enamel compositions. Examples of such known plasticizers include tricresyl phosphate, dibutyl tartrate, benzyl benzoate, tributyl phosphate, butyl acetyl ricinoleate, butyl glycolate, butyl stearate, sucrose acetate isobutyrate, triphenyl phosphate, triethyl citrate, camphor, castor oil, esters of citric, stearate, phalic, oleic, phosphate, butyric and benzoic acid, glyceryl triacetate and glyceryl triproprionate, 2,2,4-trimethyl-1,3-pentandiiol diisobutyrate and mixtures thereof. The nail enamel compositions of the present invention also contemplate the use of phthalate type plasticizers either alone or in combination with the aforementioned plasticizers, for example, diamylphthalate, dibutyl phthalate, diethyl phthalate, dioctyl phthalate, dibutoxy ethylphthalate and mixtures thereof. One preferred combination of plasticizers includes a mixture of dibutyl phthalate and sucrose acetate isobutyrate. Plasticizers included in the compositions of the present invention are in amounts sufficient to provide acceptable flexibility to the nail enamel film on the human or synthetic nail surface.
The nail enamel compositions of the present invention also include one or more organic solvents such as those generally used in conventional nail enamel compositions. Examples of these solvents include ethyl acetate, methyl acetate, ethanol, isopropanol, propyl acetate, n-butanol, xylene, DI acetone alcohol, aromatic (containing phenyl groups), amyl acetate, ethers, ketones, alkanes for example, pentane, cyclopentane, hexane, toluene, heptane, cyclohexane, cyclic ethers for example, tetrahydrofuran and 1,4-dioxane, cellosolve, butyl cellosolve acetate, cellosolve acetate, methyl cellosolve acetate, butyl cellosolve, ethyl cellosolve, phenylated solvents for example, xylene, esters of acetic acid for example, methyl acetate, ethyl acetate, n-butyl acetate, chlorinated hydrocarbons for example, methylene chloride, chloroform and methylchloroform. The aforementioned solvents can be used alone or in mixtures thereof. In general, the amount of solvent used in the compositions of the present invention range from about 80 to about 96% by weight, and preferably about 85 to about 90% by weight of the composition.
The mirrorlike appearance of the nail enamel composition is provided by the presence of aluminum platelets sold under the mark Metalure(copyright). The Metalure(copyright) aluminum platelets have a minimum aspect ratio of 1.0 and a maximum aspect ratio of about 5.2, the mean being about 1.507. The aspect ratio of the aluminum platelets is defined as the ratio of the major dimension (length) to the minor dimension (width). The Metalure(copyright) aluminum platelets have a particle size distribution as follows:
It has been reported that these aluminum platelets will not destabilize under high sheer. However, excessive mixing can potentially cause mechanical breakage and attrition of the optimized particle size distribution, resulting in reduced brilliance. To this end, it is contemplated that mixing in mechanical mills such as ball or sand mills would not be desirable in making nail enamel compositions in accordance with the present invention. The nail enamel compositions of the present invention may include aluminum platelets in an amount ranging from about 0.1 to about 5% by weight, and preferably in the range of about 0.3 to about 1.5% by weight of the composition.
Additionally, secondary pigments and/or organic colorants can be added to the compositions to provide cosmetically acceptable shades and to pacify the films. Pigments and/or organic colorants for use in the present invention may include any of those pigments or organic colorants which are generally known for use in nail enamel compositions. For example, pigments can include cosmetic grade or purified titanium dioxide, yellow and red iron oxides, bismuth oxychloride, iron blue, iron black, mica particles, ultramarine blue, DandC Red #7, chromide oxide greens, carbon black, lampblack and the like. Other pigments which may be used in compositions according to the present invention may include the Lake pigments, for example, DandC Red #6 barium Lake, DandC Red #7 calcium Lake and the like.
In addition to the above named pigments, there may also be included titanated micas, polyethylene teraphthalates and pearl essence which is a suspension of crystalline guanine in nitrocellulose and solvents, as well as other additives which will affect the appearance of the pigment. The amount of pigment in the compositions of the present invention will vary as a function of the type of pigment and other components included in the composition.
It is useful to include a suspending agent for enhancing the suspension of the aluminum platelets or other pigments in the other components of the nail enamel composition. A number of suspending agents, either alone or in combination, which are generally used in conventional nail enamel compositions may be used to produce compositions according to the present invention. For example, suspending agents include colloidal clays, montmorillonite clays, especially stearalkonium hectorite, stearalkonium bentonite, fumed silica, and mixtures thereof. One preferred combination of suspending agents include bentonite and a modified lower molecular weight polymeric urea available from BYK-Chemie USA, Wallingford, Connecticut sold under the name BYK-410. The suspending agent is present in the compositions of the present invention in amounts sufficient to produce a gel, preferably a colloidal gel. It is also contemplated that the polymeric urea can be used alone as a suspending agent.
In addition to the above described components, the nail enamel compositions of the present invention may also include additional additives including stabilizers, thixotropic agents, UV light absorbers such as ectocrylene and benzophenone-1, fragrances, moisturizers and medicants, depending on the intended result. These components are well known in the art and may be included in amounts well within the teachings of the prior art.
The incorporation of higher molecular weight components into the nail enamel composition of the present invention has the tendency to increase the composition viscosity. To maintain the composition in a flowable state to allow smooth and even application to one""s nails, the percentage of solids in the composition can be reduced. By way of example, the solid content of the nail enamel compositions of the present invention ranges from about 4 to about 20% by weight, and preferably from about 10 to about 15% by weight.
The nail enamel compositions in accordance with the present invention can be manufactured by thoroughly and intimately mixing together all the components in the amounts described in accordance with the present invention. Examples of satisfactory equipment and how to use then are readily apparent to one of ordinary skill in the nail enamel art.
In order to evaluate the mirror appearance of various nail enamel compositions prepared which include aluminum platelets, an instrument known as a goniophotometer was used. A goniophotometer is an instrument for measuring the angular distribution of reflected or transmitted light. In this regard, the mirrorlike appearance of nail enamel compositions which include aluminum platelets can be described by its gloss characteristics. The term xe2x80x9cglossxe2x80x9d is defined in ASTM standard E284(3) entitled Terminology of Appearance as angular selectivity of reflectance, involving surface-reflected light, responsible for the degree to which reflected highlights or images of objects may be seen as superimposed on a surface. Angular selectivity falls into various types such as specular gloss, sheen and haze. xe2x80x9cSpecular glossxe2x80x9d is defined in the aforementioned ASTM standard as the ratio of flux reflected in specular direction to incident flux for a specified angle of incidence and source and receptor angle apertures. xe2x80x9cSheenxe2x80x9d is defined in the aforementioned ASTM standard as the specular gloss at a large angle of incidence for an otherwise matte specimen. Haze in coating films is often designated xe2x80x9creflection hazexe2x80x9d because in plastics there is encountered a near-forward scattering in transmission that is designated transmission haze. The aforementioned ASTM standard defines xe2x80x9chazexe2x80x9d in reflection as percent of reflected light scattered by a specimen having a glossy surface so that its direction deviates more than a specified angle from the direction of specular reflection.
One instrument suitable for measuring the properties of haze and gloss of a film is available from BYK Gardner USA of Columbia, Md., Catalog No. LGB-4601. The haze-gloss instrument is constructed in accordance with ASTM standard E430-97 entitled Method for Measurement of Gloss of High Gloss Surfaces by Goniophotometry.